Al-Ani AH, Antoun JS, Thomson WM Hypodontia: an update on its etiology, classification, and clinical management. Biomed Res Int. 2017; 2017
Stockton DW, Das P, Goldenberg M Mutation of PAX9 is associated with oligodontia. Nat Genet. 2000; 24:18-19
Mostowska A, Kobielak A, Trzeciak WH. Molecular basis of non-syndromic tooth agenesis: mutations of MSX1 and PAX9 reflect their role in patterning human dentition. Eur J Oral Sci. 2003; 111:365-370
Dhamo B, Kuijpers MAR, Balk-Leurs I Disturbances of dental development distinguish patients with oligodontia-ectodermal dysplasia from isolated oligodontia. Orthod Craniofac Res. 2018; 21:48-56
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Brook AH, Griffin RC, Smith RN Tooth size patterns in patients with hypodontia and supernumerary teeth. Arch Oral Biol. 2009; 54:S63-70
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Park H, Song JS, Shin TJ WNT10A mutations causing oligodontia. Arch Oral Biol. 2019; 103:8-11
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Non-syndromic oligodontia, the agenesis of six or more teeth, has a prevalence of 0.14–0.25%. Genetic, epigenetic and environmental influences affect expression. Three brothers presented with agenesis of 14, 21 and 23 permanent teeth, respectively. They were medically well, with no relevant family history. Each case presented with caries, microdontia and attritive tooth surface loss. Comprehensive care was delivered in each case by undergraduate dental students. Individualized prevention and stabilization were completed before referral for multidisciplinary long-term planning. Primary dental care practitioners are instrumental in delivering preventive care and stabilizing the dentition in cases of dental anomaly, while sharing care with specialist teams.
CPD/Clinical Relevance: An unusual presentation of non-syndromic oligodontia relevant to primary dental care practitioners who are likely to provide the first clinical contact and referral to the wider multidisciplinary team.
Article
Hypodontia, or tooth agenesis, is the most prevalent craniofacial malformation in humans.1,2 Hypodontia may be associated with a syndrome or be related to a non-syndromic isolated trait, and is a phenotypically heterogenous condition. The prevalence of hypodontia in the UK is approximately 8%; however, the developmental absence of permanent canines, first and second permanent molars is rare, and most commonly presents in patients with severe forms of syndromic oligodontia.1 Third molars are the most commonly developmentally absent teeth, followed by upper lateral incisors or lower second premolars.
Oligodontia refers to the absence of six or more permanent teeth (excluding the third molars) in the absence of an associated systemic disorder.3 Prevalence of oligodontia in the general population is estimated to be 0.14–0.25%.1,4 Children with ectodermal dysplasia tend to exhibit oligodontia, microdontia, hypohidrosis and sparse fine hair.5 The impact of oligodontia on oral health-related quality of life may concern aesthetics, function and treatment complexity.6
The aetiology of tooth agenesis is a complex dynamic relationship between genetic, epigenetic and environmental influences, including mutations of MSX1, PAX9 and WNT10A genes.3,7–13 Reduced PAX9 protein may specifically affect molar development.4 In monozygotic twin studies, twins often exhibit variance in expression of genes, further indicating the role of environmental factors.14–16
The primary dental care practitioner has an important role in the management and shared care of children with oligodontia. This task includes the recognition of developmentally absent teeth, informing children and their families of the diagnosis, delivering individualized and optimal preventive dental care, and referral to specialist paediatric dentistry services. Furthermore, the primary dental care practitioner is frequently asked, as part of a shared-care treatment plan, to carry out check-ups, to deliver routine care planned to maintain a caries-free dentition, to help children acclimatize to the dental environment, and to prepare them for impending and complex multidisciplinary care. The primary dental care practitioner also acts as the established trusted contact in the midst of a multitude of consultant-led hospital dental visits. It is, therefore, important that the whole dental team understands the hurdles faced by children with oligodontia, to enable them to persevere and to access optimal outcomes.
This case series presents three siblings, including dizygotic twins and their elder brother, who presented to a specialist paediatric dentistry team with varying degrees of oligodontia, following referral from their primary dental care practitioner who had recognized failure of dental development and eruption. None of the three brothers had prior experience of dental intervention, and they each had varying degrees of unmanaged dental disease and dental anxiety, necessitating varied approaches to care. An MCDAS(f) scale (Modified Child Dental Anxiety Scale faces version) was used to record dental anxiety at presentation. The MCDAS(f) is a reliable and valid measure of dental anxiety in children. Total scores on the MCDAS(f) range from 5 (little or no dental anxiety) to 40 (extreme dental anxiety).17
Presentation
The presenting complaints and clinical findings were varied (Table 1). There was no known family history of the developmental absence of teeth. All three children were fit and well. Extra-oral examination did not suggest the presence of any concomitant syndrome, such as ectodermal dysplasia.
Case
Age (years)
Examination
Number of developmentally absent teeth
Permanent tooth agenesis
Case 1 GC
8
Mixed dentitionTooth wear and caries of the primary molars (Figure 1).Diminutive UR5Asymptomatic with no complaints
All three children received targeted, individualized oral health advice in line with accepted guidelines for children at risk of caries.18 When considering restorative intervention, the placement of preformed metal crowns (PMCs) to seal in caries via the Hall technique is associated with optimal outcomes in appropriately selected cases.19 Recent evidence suggests that there may be little difference in the outcomes of caries management in primary teeth between conventional restorations, PMCs or a best-practice preventative approach.20 Young children, their families and dentists may have a preference for PMCs rather than a conventional restoration for primary molars, negating the need to achieve local anaesthesia and the dry field required for a bonded restoration, and in light of recent restrictions on the use of amalgam.21 In the case of carious primary molars that lack permanent successors, and in the interests of long-term maintenance of these teeth and acclimatization to the dental environment, a decision was made for these siblings to restore with either PMCs using the Hall technique or with composite, depending on patient compliance and caries extent. In the case of carious permanent molars, a decision was made to restore with composite.
Case 1
GC had an MCDAS(f) score of 22. With the use of behavioural modification techniques, such as tell-show-do, rewarding helpful behaviours and stop signals, he was compliant for the placement of PMCs via the Hall technique on LLD and LRD (Figures 1 and 2). The patient was reviewed at 3-monthly intervals for a period of 12 months, following which a referral was made for multidisciplinary care with specialists in paediatric dentistry, orthodontics and restorative dentistry.
Figure 1. (a–c) Radiographic examination of Case 1, GC.Figure 2. (a–c) Post-operative photographs for Case 1, GC.
Case 2
FC had an MCDAS(f) score of 38. He was unable to tolerate bitewing radiographs or dental treatment. An examination under general anaesthesia took place, during which composite restorations were placed on LLD, LRE and URD and a PMC was placed on the more extensively carious ULE. Caries extended to pulp in URE, ULD and LRD, which were extracted (Figures 3 and 4). FC returned to clinic to receive targeted preventive care and acclimatization to the dental environment, following which he was able to cooperate for bitewing radiographs and application of fissure sealants. The patient was reviewed at 3-monthly intervals for a period of 12 months, following which a referral was made for multidisciplinary care with specialists in paediatric dentistry, orthodontics and restorative dentistry.
Figure 3. Radiographic examination of Case 3, FC.Figure 4. (a–c) Post-operative photographs for Case 2, FC.
Case 3
HC had an MCDAS(f) score of 14. He was compliant for restoration of the UL6 and LR6 with local anaesthetic, and fissure sealant of the remaining molars (Figures 5 and 6). Following a 3-month recall interval, the patient was referred for multidisciplinary care with specialists in paediatric dentistry, orthodontics and restorative dentistry.
Figure 5. (a–c) Radiographic examination of Case 3, HC.Figure 6. (a–c) Post-operative photographs for Case 3, HC.
Discussion
This case series demonstrates variable expression of non-syndromic tooth agenesis in three siblings in the absence of medical or developmental comorbidities. Case reports of apparently isolated oligodontia are exceedingly rare, particularly within the same family.22,23 The extent and variability of tooth agenesis in this sibling series, and the absence of parental phenotype or family history, is of interest. Furthermore, the presentation of three siblings from the same family home with varying presenting complaints, preventable disease states and dental anxieties, makes this case series unique.
Individualized treatment planning in response to these presenting features, helped each sibling to improve their oral health and prepare for multidisciplinary intervention. This is particularly notable with the twins, who might have been expected to experience similar environmental influences on oral health and dental experience, yet they exhibited dental diseases of varied aetiology and extent, and a diverse ability to accept treatment. The children attended appointments with their mother, who expressed her own dental anxiety. This may have affected individual responses to proposed dental interventions.24
The long-term management of the siblings may include orthodontic space redistribution in the permanent dentition. Depending on the number and position of teeth present, orthodontic intervention may include space closure, or space maintenance, with prosthetic rehabilitation. Patients with oligodontia may meet specific eligibility criteria for NHS-funded prosthetic rehabilitation with implants once they have completed facial growth, under the care of a multidisciplinary team.28
Maintenance of teeth present in children with hypodontia may enhance orthodontic management options for future space redistribution, while concomitantly reducing the potential number of implant units required. Preventable diseases, including caries and tooth wear, complicate treatment planning and increase the need for prosthetic rehabilitation. It is, therefore, the goal of the primary dental care practitioner to deliver targeted preventive care to patients with hypodontia, to include targeted fluoride therapy, fissure sealants, oral hygiene advice, diet analysis, and 3-monthly clinical recall and 6-monthly radiographic review for those at high caries risk, in line with widely accepted guidelines.18,20,29
As the siblings age, their presenting complaints are likely to evolve. The psychosocial impact of oligodontia may impact quality of life, and should be considered alongside maintenance of oral health and function in any future multidisciplinary planning and shared care with the primary dental care team.
Access to primary dental care services for children in England is poor, with 41.4% not visiting an NHS dentist in 2018.25 These cases highlight the importance of early access and preventive care for patients at high risk of dental disease, and particularly for patients with complex dentitions where the consequences of preventable tooth loss are arguably more severe. Approximately one-quarter of 5-year-old children in England have visible decay, and this rises to one-third of 5-year-old children in the northwest of England, where this case series is set.26,27 Hence, the child population has a critical need for primary care-led, evidence-based preventive dental care, and for facilitated access via campaigns such as the British Society of Paediatric Dentistry's ‘Dental Check by 1’. For all children who are not brought as regular dental attenders, the importance of each primary care contact is heightened.
The general dental practitioner serves as a gateway to multidisciplinary care and as an established contact to the family. Early recognition of abnormalities of tooth eruption allows prompt referral to a specialist in paediatric dentistry. Paediatric dentists can assist in the investigation and diagnosis of dental anomalies, while the known and trusted general dental practitioner continues to deliver preventive care in the local family unit. The paediatric dentist can make onward referral to a multidisciplinary team at an appropriate developmental age, while planning interventions to address aesthetic and functional concerns as soon as they arise. Furthermore, early paediatric specialist involvement may be helpful in patients with dental anxiety who require pharmacological intervention, supported by acclimatization and non-pharmacological behavioural modification that is most appropriately delivered in the primary care setting. Patients with oligodontia may also wish to access the advice of a geneticist, which the paediatric dentistry team is well placed to facilitate. Communication between primary care and specialist teams is key to ensuring shared care with optimal patient outcomes and experiences for children with oligodontia.
